Andrews says he was surprised by the success of the program because depression patients often suffer from a lack of motivation.

"By definition people with depression lack effort and energy," he says.

But Andrews says the correspondence they received from the patients indicated they were keen to overcome their depression.

End of the therapist?

The success of the program also brought into question traditional theories of face-to-face treatment, he says.

"We've always been trained that the transference between clinician and patients was the motivation for change."

"To find that we don't need that is a bit scary," he says.

But Andrews says psychologists and psychiatrists won't be out of a job because there is more to mental health professions than treating 'stock standard' depression and that personal contact is still important.

Andrews and his team also examined the effectiveness of internet-based treatments for other mental disorders such as anxiety, which displayed similar success.

He says ideally the internet treatment will enhance existing clinical treatments rather than replace them.

"I think this has very wide application. We are talking about rolling this out to rural divisions of general practice for GP's to use."